Are Viruses Worse for Morning People?

We know that we’re more likely to get sick when we’re tired or run down—our bodies are more vulnerable to infection during those times. Now, scientists are trying to determine if there’s a time of day when infection is worse. A new study suggests there is—catching a virus in the morning may be more dangerous than at other times of the day.

Viral infections begin when the virus invades cells in the body, takes over the mechanism of the cells, and replicates within the cells. Our cells change considerably throughout the sleep-wake cycle, also called the 24-hour body clock or circadian rhythm, and are more susceptible to germs at certain times. In animal studies, mice that were infected with a virus in the morning developed a viral load ten times higher than those infected with the same virus later in the day.

This may explain why, when coming down with a cold, we often feel okay in the morning and begin to feel much worse as the day goes along. If further research confirms the results of this study, it may help control the spread of viruses. During flu season, for example, staying home in the early part of the day could reduce your risk of infection.